1. Field of the Invention
The present invention relates to the field of liquid crystal displaying, and in particular to a method for manufacturing liquid crystal display panel.
2. The Related Arts
Liquid crystal display (LCD) has a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and is thus widely used. Most of the LCDs that are currently available in the market are backlighting LCDs, which comprise a liquid crystal display panel and a backlight module. The operation principle of the liquid crystal display panel is that liquid crystal molecules are interposed between two parallel glass substrates and electricity is applied to the glass substrates to control variation of orientation of the liquid crystal molecules in order to refract light emitting from the backlight module for generating images.
A liquid crystal display panel is generally composed of a color filter substrate, a thin film transistor (TFT) substrate, and liquid crystal (LC) and sealant interposed between the CF substrate and the TFT substrate. A general manufacturing process comprises a front stage of array process (including thin film, yellow light, etching, and film stripping), an intermediate stage of cell process (including bonding TFT substrate and the CF substrate), and a rear stage of assembling process (including mounting drive ICs and printed circuit board). The front stage of array process generally makes the TFT substrate for controlling the movement of liquid crystal molecules. The intermediate stage of cell process generally introduces the liquid crystal between the TFT substrate and the CF substrate. The rear stage of assembling process generally integrates the drive ICs and the printed circuit board to drive the liquid crystal molecules to rotate for displaying images.
An active matrix liquid crystal display (AMLCD), which is today's main stream, generally uses a bottom gate alternation TFT structure 300 (see FIG. 1) to serve as a switching element and this generally for the following considerations. First, the bottom gate may provide a light-shielding arrangement to avoid influence on stability of TFT component due to photo current from an active layer (which is generally a channel layer made of hydrogenated amorphous silicon (a-Si:H)) caused by irradiation of back light. Second, in operation, sequentially depositing SiNx (silicon nitride)/a-Si:H (hydrogenated amorphous silicon)/n+a-Si:H (nitrogen doped hydrogenated amorphous silicon) causes least influence on each interface. The commonly known top gate structure TFT 300′ (see FIG. 2) is not used because of leakage current caused by irradiation of back light.
A commonly used COA (Color Filtering On Array) arrangement is to still arrange a black matrix as a layer of color filtering to block external interfering light and leakage of back light and the R, G, B pixels 310 are partially coated on a layer of the thin-film transistor 300″ (see FIG. 3), wherein the TFT portion uses the bottom gate alternation structure. The manufacturing process is complicated, making the cost relatively high and the yield rate low.